Transcript EE 316 Computer Engineering Junior Lab

EE 316
Computer Engineering Junior Lab
Project 1: Traffic Light Controller
The traffic Light Controller
Source: John Wakerly
Specifications
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EW street is heavily traveled
NW street is lightly traveled
Pedestrian can halt traffic for crossing but not create traffic
jam
EW, NS and Pedestrian traffic signals have at least Green
and Red lights
Each green light is on for 5, 9 and 4 secs, respectively
Remember!
The design cycle involves:
 Careful planning
 Learning
 Setting specific goals
 Designing
 Building
 Testing and
 Troubleshooting
Design Methodology
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Study the details in the Specification (read between lines).
 Partition the design problem into smaller sub-components
or parts.
 Create specifications for each part and their interactions
with others. Design and build each of the basic
components/parts and test them thoroughly before
attempting to combine with or connect to other subcomponents.
 Predict what to expect at each step and decide how would
you test your hypothesis with measurements.
Design Methodology (contd.)
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Test the circuit and verify if your design worked as
expected
Troubleshoot your circuit if design does not work. Pay
attention to power/ground lines, interfaces/ports (pin
diagram and wires), fanout, drive currents (TTL vs.
CMOS), bad connections, wrong delays etc.
Modify the design if needs and repeat the steps.
Write every step in the Notebook (legible documentation
please). Draw circuit diagrams, pin diagrams chips, test
and measurement results, troubleshooting, and design
changes etc.
A partial list of subcomponents
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A state machine (sequential circuit)
 Counter/timer
 Clock generator circuit
 7-segment displays
 LEDs to be used as traffic signals
 PC and XP compatible software
The state machine and the controller
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State diagram/table and outputs
 State assignment and K-maps
 A timer/counter to be used as a controller to
trigger transition from one state to the other
depending on the inputs
Counter/Timer and clock
generation circuit
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Identify a TTL or CMOS based 7400 series chip
that would be appropriate for this project
 Study the data sheet carefully before using any
chip
 Verify the clock frequency with an oscilloscope.
 Use the digital logic analyzer to verify design
7-Segment Displays and LEDs
You will need appropriate
Drivers for the two kinds
Of displays.
Also, remember
LEDs/displays can be
destroyed very easily. Use
resistors to limit current
http://www.play-hookey.com/digital/experiments/seven_seg_led.html
More details
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Add bypass capacitors between VDD and
GND if you cannot explain state skips or
strange behaviors.
The IEEE 1284 parallel
interface standard
Parallel ports are used for connecting a computer (host) to
a printer or certain other peripheral devices over a parallel
(eight bits of data at a time) physical and electrical
interface.
Parallel ports conform to the specifications of document of
the Institute of Electrical and Electronic Engineers (IEEE)
called IEEE Std 1284-1994: Standard Signaling Method
for a Bi-directional Parallel Peripheral Interface for
Personal Computers, or IEEE 1284 for short.
http://whatis.techtarget.com/definition/0,,sid9_gci213469,00.html
http://www.lavalink.com/fileadmin/white_papers/ieee1284_parallel_ports.pdf
Modes of operation
(The IEEE 1284 standard)
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Compatibility mode (Default “Forward” mode)
 Nibble mode (4-bit “reverse” mode)
 Byte mode (8-bit “reverse” mode)
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EPP mode (Enhanced Parallel Port mode)
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ECP mode (Enhanced Capability Port mode)
Forward: Host to Peripheral
Reverse: Peripheral to Host
Source: http://www.lvr.com/files/ppc1.pdf
25 Pin D-sub or IEEE 1284-A connectors
http://www.lavalink.com/fileadmin/white_papers/ieee1284_parallel_ports.pdf
36 Pin Centronics or IEEE 1284-B connectors
http://www.lavalink.com/fileadmin/white_papers/ieee1284_parallel_ports.pdf
IEEE-1284 compliant
Parallel Printer Cables
Connector Types
IEEE-1284 Printer Type “A” Connector (DB25) This is the connector
most commonly used as the computers parallel port output.
IEEE-1284 Printer Type “B” Connector (CN36) This is the most
commonly used connector for the end of the cable that goes to the
printer.
IEEE-1284 Printer Type “C” Connector (HPCN36) This is a new
connector for the printer end of the cable.
http://www.ramelectronics.net/html/ieee-1284_printer_cables.html
DB-25 Female D-type Connector
(on the computer)
•8 output pins accessed via the DATA Port (bidirectional)
•5 input pins (one inverted) accessed via the STATUS Port (peripheral to HOST)
•4 output pins (three inverted) accessed via the CONTROL Port (output only)
•The remaining 8 pins are grounded
http://www.doc.ic.ac.uk/~ih/doc/par/index.html#index
Addressing
Standard parallel port uses three contiguous addresses:
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3BCh, 3BDh, 3BEh (LPT1)
378h, 379h, 37Ah
(LPT1, LPT2)
278h, 279h, 27Ah
(LPT1, LPT2, LPT3))
First Address -- Port base address (data registers)
Second Address -- (base+1) Port’s status registers
Third Address – (base+2) Ports Control Registers
In our lab we have a PCI parallel
card that uses the
Following address:
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DF18h, DF19h, DF1Ah
Parallel port output drive
capabilities
The outputs of the data registers are filtered through
A 27 Ohm resistor and a 2.2 nF capacitors.
The numbers can vary substantially between different port types. For fast transitions and
more drive currents it is best to use Schmitt-trigger buffers/inverters at the receiving end.
http://www.hut.fi/Misc/Electronics/circuits/lptpower.html
Project Reports
Each project writer is to submit a project report containing:
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Summary (Executive summary or abstract)
Design Problem Statement
Problem Decomposition
Significant details of design process
Alternative designs
Design Documentation
• Schematics documenting your hardware design
• HDL and test bench files (for future reports
• Software design, i.e. flowchart or pseudocode
Testing:
• Module level testing
• Specification testing
Performance Results and Analysis
References
References
http://www.lvr.com/files/ppc1.pdf
http://whatis.techtarget.com/definition/0,,sid9_gci213469,00.html
http://www.doc.ic.ac.uk/~ih/doc/par/index.html#index
http://www.epanorama.net/circuits/parallel_output.html
http://www.hut.fi/Misc/Electronics/circuits/lptpower.html